The overall goal of this proposal is to examine the structure, function and regulation of type II binding sites in normal and neoplastic cells. Type II binding sites are receptors for methyl-hydroxyphenylactate and are thought to be involved in the inhibition of cell proliferation. In order to accomplish this general goal the following specific aims are proposed. The type II binding site will be purified from chick oviduct and/or rat uterus. This will be done by size, charge and affinity chromatography. Purified type II antigen will be used to produce monocolonal and polyclonal antibodies. These will be use for qualitative and quantitative analyses of type Ii sites and the estrogen receptor. Antibodies to type II sites will also be use, along with oligonucleotide probes, to screen cDNA libraries for the type II gene. The gene will be characterized and the cDNA used as a pulse for the study of the regulate of type II site gene expression. Regulation of type Ii expression will be examined in achieving expression systems, transgenic mice, normal and neoplastic cells in culture and in intact and ovariectomized animal. These experiments should produce a much better understanding of the role of type Ii site expression and regulation in the biology of normal, estrogen regulated and neoplastic cell growth.